Not Applicable
Not Applicable
Not Applicable
Generally, a shield electric wire has a core wire, an inner covering portion that is made of resin and that covers the core wire, braided wires situated on an outer periphery of the inner covering portion, and an outer covering portion that covers the braided wires. The outer covering portion is formed of, for example, heat-resisting PVC (heat-resisting vinyl chloride resin) while the inner covering portion is formed of, for example, cross-linked polyethylene. A grounding electric wire that is connected to the shield wire has a core wire and a covering portion made of resin and covering the core wire.
When connecting the shield electric wire and the grounding electric wire together, a method that is based on ultrasonic welding can be used, too.
The present invention relates to a joining method of a covered wire that comprises electrically conductively connecting a covered wire to another member, and a covered wire with a low-melting-point metal layer therein that is used for performing this method.
However, in a case where merely ultrasonically welding the shield electric wire and the grounding electric wire together, the braided wires and the core wire are merely in contacted relationship with each other. Therefore, there is the possibility that the reliability on the electrical conduction therebetween will be insufficient.
Thereupon, an object of the present invention is to provide a joining method of a covered wire that enables the performance of a highly reliable electrically conductive connection, and a covered wire with a low-melting-point metal layer therein that is used for performing this method.
To attain the above object, in a joining method of the present invention, first, connection portions of first and second conductive members are pinched between resinous chips. At least one of the first and second members is constituted by a covered wire having a conductor wire portion and a resin-made covering portion which covers an outer periphery of the conductor wire portion. At least a part of the conductor wire portion of the covered wire is covered beforehand by a low-melting-point metal layer having a significant value of thickness. Next, the covering portions corresponding to the connection portions are eliminated by heating and pressurization. And both of the resinous chips are then welded to each other, whereby the connection portions are hermetically sealed. The first and second members are electrically conductively connected together by the welding of the low-melting-point metal layer.
According to this method, by the low-melting-point metal layer being dissolved, the first and the second members are electrically conductively connected together. For this reason, an intermetallic-bond portion increases with the result that the reliability on the electrical conduction is enhanced. In addition, there is no need to use a low-melting-point metal layer as a separate piece of parts. Therefore, it is possible to prevent an increase in the cost for parts control, etc. Handling the parts is also easy.
Each of the first and the second members may be constituted by the covered wire having an outer periphery of the conductor wire portion covered by the resin-made covering portion.
The other of the first and the second members may be constituted by a terminal.
A covered wire has a conductor wire portion, a covering portion that covers the conductor wire portion, and a low-melting-point metal layer having a significant value of thickness that covers at least a part of the conductor wire portion. Connection portions of the covered wire and another member are pinched between the resinous chips. The covering portions corresponding to the connection portions are eliminated by heating and pressurization. And both of the resinous chips are then welded to each other, whereby the connection portions are hermetically sealed.
The conductor wire portion may be a plurality of sets of elemental-wire congregations. And each elemental-wire congregation may have a plurality of elemental wires and a low-melting-point metal layer that covers the elemental wires from around the same and that connects these elemental wires to one another. As a result of this, the intermetallic-bond portion further increases with the result that the reliability on the electrical conduction is enhanced.
The proportion of the low-melting-point metal layers based upon a total cross-sectional area of the low-melting-point metal layers and the conductor wire portions may be from 12% inclusive to 18% inclusive. As a result of this, the intermetallic-bond portion more reliably increases with the result that the reliability on the electrical conduction is enhanced.
The low-melting-point metal layer is formed of metal that melts due to the generated heat that is provided at least by ultrasonic welding of the resin. As a result of this, forming the layer can be easily done.